There's a veggie/wholefood stand in Borough market, around the Stoney Street/Winchester walk area, near to the Monmouth coffee stand. I know the market's only there fridays and saturdays, but I hope this helps!
Also, Baldwins on Walworth Road is really good - a bit out of your way, but worth a look!

try Fareshares at 56 Crampton Street SE17
bit anarcho-hippy.
Take your own bag and write the prices down as you select items from the shelves.
be kind to volunteers, coz they work for nothing.

I like the *idea* of Fare Shares. I used to be warden in the big blue student residence on nearby Walworth Rd above Dragon Castle, and was keen to drum up custom for them, but they don't seem, as they say, bovvered.

There are no carrier bags (which is good), but also no bags or containers for bulk rice, pulses, oats, etc. and that is silly. I saw several people abandoning their shopping because they couldn't carry them. The opening hours are eccentric, irregular and unpublicised, and unfortunately the voluntary staff are clueless and/or argumentative. I got a juvenile lecture about saving the earth when I suggested they consider getting a stock of paper bags, and was practically told to go back to Tesco.

I am not saying they should be going all out to make profits, that is not in the spirit, but some basic retail and social skills would be good.